From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-3.6 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 854FBC10F14 for ; Thu, 10 Oct 2019 13:41:22 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 4A7EE2067B for ; Thu, 10 Oct 2019 13:41:22 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=shipmail.org header.i=@shipmail.org header.b="Rix0aEWR" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 4A7EE2067B Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=shipmail.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id DEB996B0003; Thu, 10 Oct 2019 09:41:21 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id D9BB56B0005; Thu, 10 Oct 2019 09:41:21 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id CB2658E0003; Thu, 10 Oct 2019 09:41:21 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0168.hostedemail.com [216.40.44.168]) by kanga.kvack.org (Postfix) with ESMTP id AA6216B0003 for ; Thu, 10 Oct 2019 09:41:21 -0400 (EDT) Received: from smtpin29.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with SMTP id 52098181AC9AE for ; Thu, 10 Oct 2019 13:41:21 +0000 (UTC) X-FDA: 76027986762.29.quill33_800d9eb2d6f40 X-HE-Tag: quill33_800d9eb2d6f40 X-Filterd-Recvd-Size: 3353 Received: from ste-pvt-msa2.bahnhof.se (ste-pvt-msa2.bahnhof.se [213.80.101.71]) by imf34.hostedemail.com (Postfix) with ESMTP for ; Thu, 10 Oct 2019 13:41:19 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by ste-pvt-msa2.bahnhof.se (Postfix) with ESMTP id 741453F49B; Thu, 10 Oct 2019 15:41:18 +0200 (CEST) Authentication-Results: ste-pvt-msa2.bahnhof.se; dkim=pass (1024-bit key; unprotected) header.d=shipmail.org header.i=@shipmail.org header.b=Rix0aEWR; dkim-atps=neutral X-Virus-Scanned: Debian amavisd-new at bahnhof.se Authentication-Results: ste-ftg-msa2.bahnhof.se (amavisd-new); dkim=pass (1024-bit key) header.d=shipmail.org Received: from ste-pvt-msa2.bahnhof.se ([127.0.0.1]) by localhost (ste-ftg-msa2.bahnhof.se [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id cahSb6bMUdIh; Thu, 10 Oct 2019 15:41:17 +0200 (CEST) Received: from mail1.shipmail.org (h-205-35.A357.priv.bahnhof.se [155.4.205.35]) (Authenticated sender: mb878879) by ste-pvt-msa2.bahnhof.se (Postfix) with ESMTPA id 493113F218; Thu, 10 Oct 2019 15:41:17 +0200 (CEST) Received: from localhost.localdomain.localdomain (h-205-35.A357.priv.bahnhof.se [155.4.205.35]) by mail1.shipmail.org (Postfix) with ESMTPSA id 0DD4D36016C; Thu, 10 Oct 2019 15:41:17 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=shipmail.org; s=mail; t=1570714877; bh=n0r0/gr5DGR8PKfDTpl5xOseUsgi8gjV64mOMzX31mg=; h=From:To:Cc:Subject:Date:From; b=Rix0aEWR6MmQ3IMpwzhAJ7nxL1ZmI7koM15not/pYLFsz5Q96lP3VpexvNYEOq43t IevhIYzceltokMIkYLDVJUA69uoPPp3B95Iuam64ihG5ZXnj5raBIayjng0fq1GQQr 3RibwTeSADJ13s7gNhiUWxjcFTy9i5HZh8EHcKEI= From: =?UTF-8?q?Thomas=20Hellstr=C3=B6m=20=28VMware=29?= To: linux-kernel@vger.kernel.org, linux-mm@kvack.org, torvalds@linux-foundation.org, kirill@shutemov.name Cc: =?UTF-8?q?Thomas=20Hellstr=C3=B6m?= Subject: [RFC PATCH 0/4] mm: pagewalk: Rework callback return values and optionally skip the pte level Date: Thu, 10 Oct 2019 15:40:54 +0200 Message-Id: <20191010134058.11949-1-thomas_os@shipmail.org> X-Mailer: git-send-email 2.21.0 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Bogosity: Ham, tests=bogofilter, spamicity=0.079143, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: This series converts all users of pagewalk positive callback return value= s to use negative values instead, so that the positive values are free for pagewalk control. Then the return value PAGE_WALK_CONTINUE is introduced. That value is intended for callbacks to indicate that they've handled the entry and it's not necessary to split and go to a lower level. Initially this is implemented only for pmd_entry(), but could (should?) at some point be used also for pud_entry(). Finally the mapping_dirty_helpers pagewalk is modified to use the new val= ue indicating that it has processed a read-only huge pmd entry and don't wan= t it to be split and handled at the pte level. Note: This series still needs some significant testing and another re-aud= it to verify that there are no more pagewalk users relying on positive retur= n values.